Terminal wiring driver



Nov. 2, 1965 M. T. COLLIER 3,215,170

TERMINAL WIRING DRIVER Filed Jan. 1?, 1963 F/a Z.

INVENTOR. Maw/v 7T COLL/ER F/G. 5. M

TT'OPNEYS United States Patent 3,215,170 TERMINAL WIRING DRIVER Melvin T. Collier, 1346 11th St., Denver, Colo. Filed Jan. 17, 1963, Ser. No. 252,232 7 Claims. (Cl. 140124) This invention relates to screw and nut devices and, more particularly, to a terminal wiring attachment for use therewith.

The prior art is replete with specially designed screw and nut drivers adapted to wrap a conductor around a terminal post preparatory to fastening same down with the screw head or a nut. Some of these provide an extensible pin slidably mounted alongside the shank of the tool while others utilize a sleeve that is permanently and non-rotatably affixed to the shank for longitudinal movement between extended-operative and retracted-inoperative positions. In all of these prior art attempts at a terminal wiring tool, certain deficiencies appear which, no doubt, explain their failure to realize any appreciable degree of commercial acceptability.

Most significant among these deficiencies, of course, is their complexity which makes them much too expensive for even the specialist to use when the manufacturer is reluctant to tool up for a limited market unless he can realize a large profit. An equally important disadvantage is that the design of the prior art terminal-wiring tools is such that they cannot be used in all ordinary applications requiring a screw or nut driver due to the presence of the feature that functions to wrap the conductor around the terminal post. This means that the electrician must carry both ordinary screw and nut drivers as well as the special purpose ones designed for terminal wiring.

These prior art tools also have certain specific limitations not necessarily shared by all designs. For example, some of the devices are so constructed that whenever pressure is applied axially of the handle to seat the tip in either the slot of the screw or around the nut, the conductor-wrapping appurtenance is automatically extended and cannot be retracted unless the pressure is released. Quite obviously, it is not at all uncommon to find many situations where the wire-wrapping feature in extended position either interferes or renders impossible the performance of a given operation.

Other units provide a mechanical interlock of some type between the shank of the driver and the conductorwrapping feature which transfers the rotational movement imparted to the handle from one to the other. Of necessity, this requires the screw or nut to be turned down onto the threaded post simultaneously with wrapping the bared conductor end therearound. Unfortunately, this is not always possible. As an example, in the case of a short threaded terminal and a relatively large diameter conductor, the gap between the terminal bar and screw head or nut adapted to receive the bared conductor end can easily close to an extent where the conductor cannot enter before the desired 180 to 270 turn is completed. Accordingly, it becomes highly desirable to have the terminal wrapping element turn independently of the driver thus avoiding the above problem. Along this same line, the interlock which is usually a pin and slot arrangement or an elongated pin mounted for reciprocal movement in a tube, are subjected to a great deal of mechanical strain during the wrapping operation especially with heavy conductors. As a result, the slots widen, the pin riding therein shears off or the elongated pin bends rendering the tool useless.

Still another common deficiency is that most of the prior art tools for this purpose spring bias the wrapping element into either retracted or extended position. This ice would appear at first glance to be an advantage, however, it is not because a necessary adjunct to this is the requirement that the user must manually overcome the spring bias in order to hold the wrapping element in the position opposite to that in which it is urged by the spring. As such, the use of the tool as a nut or screw driver which is an integral function to be performed thereby in even terminal wiring applications, becomes quite difiicult.

No doubt the most significant disadvantage of the prior art terminal wiring tools remains the necessity for complete redesign of the basic screw or nut driving tool to accommodate the element which wraps the bared conductor end around the terminal post. The small hand tool market is a highly competitive one operating on small profit margins especially when considered in the light of extremely cheap foreign imports. Thus, the manufacturer is reluctant to entertain any suggestions requiring major changes in design because of the unfavorable competitive position such changes would place him in due to tool and die costs.

Thus, from the foregoing, it would seem that an ideal hand tool of the screw or nut driver type for use in bending the bared end of a conductor around a terminal post would, first of all, require no significant change in the design of the hand tool as presently fabricated for ordinary use. The terminal wrapping element, on the other hand, would be an accessory item completely demountable at will from the basic hand tool so as to leave the latter unencumbered for general use. Also, the accessory would be designed for independent rotational movement relative to the shank of the driver and include means adapted to releasably hold same in either extended or retracted position but with no spring bias in any axial direction. Finally, the accessory itself should be simple, cheap and easily adaptable for use with any of the common screw and nut driver designs.

It is, therefore, the principal object of the present invention to provide a novel and improved terminal wiring accessory for use in combination with an ordinary screw or nut driver slightly modified, where necessary, to accommodate such an accessory.

A second object is the provision of a hand tool of the type aforementioned which is ideally suited for use in fastening the bared ends of conductors to screw terminals yet is fully operable for all other applications in which a screw or nut driver are ordinarily employed.

Another object is to provide a hand tool in the nature of a screw or nut driver that includes a terminal wiring feature yet is so compact as to be practically the same size and shape as a hand tool without such a feature.

Still another objective of the invention herein disclosed is the provision of a terminal wiring tool that eliminates the necessity for turning the screw head or nut on the threaded terminal post simultaneously with the wrapping of the bared conductor end therearound although, if desired, the operation can be handled in this manner with equal facility.

An additional object of this invention is to produce a rugged multi-purpose yet specialized hand tool for use by skilled electricians as well as the handyman at a price which is little higher than a first-quality screw or nut driver alone.

Further objects are to provide a screw or nut driver in combination with a detachable terminal wiring accesssory that is versatile, easy to use by even unskilled persons, a unit that is streamlined and attractive, and a hand tool of the class described that can be operated in several different ways to accomplish the desired end result depending upon the particular wiring situation or the whim of the operator.

Other objects will be in part apparent and in part pointed out specifically hereinafter in connection with the description of the drawings that follows, and in which:

FIGURE 1 is a side elevation showing the terminal wiring attachment in section and in retracted position on a screw driver;

FIGURE 2 is an elevation quite similar to FIGURE 1 except that the attachment is shown in extended operative position and the details of the retaining spring providing frictional contact between the shank of the driver and tube of the attachment is more clearly revealed;

FIGURE 3 is a fragmentary bottom plan view showing the design of the tip on the attachment;

FIGURE 4 is a rear end elevation to an enlarged scale showing the attachment alone; and,

FIGURE 5 is a fragmentary sectional view similar to FIGURE 2 but to an enlarged scale showing the terminal wiring attachment in place on the shank of a nut driver rather than a screwdriver.

Referring now to the drawings for a detailed description of the present invention and, in particular, to FIG- URES l and 2 for this purpose, the tool has been designated in its entirety by reference numeral lit and it will be seen to include two separable parts, namely, what will be designated the driver portion 12 and the accessory portion 14. For purposes of the present description, the term driver will include both a screw driver having a bladed tip as shown in FIGURES l and 2, and a nut driver terminating in a rectangular or hexagonal socket such as is illustrated in FIGURE 5. The reason for this is that the ordinary terminal strips used in the electrical inductry may have either a non-rotatable threaded post on which a nut is mounted to fasten the conductor in place or a headed screw that threads into an internally-threaded socket. Thus, either of two different types of hand tools may be used to wire the ter minals, i.e. a screw or nut driver, and the accessory item forming the subject matter of the present invention is equally adaptable for use with both.

The driver 12 will be seen to have, in the particular form illustrated, a molded plastic handle 16 usually formed from some dielectric material which will provide the desired measure of shock protection to the user. Ordinarily, the handle is provided with angularly-spaced longitudinally extending grooves 18 that provide a better grip for the hand. In the preferred embodiment of the present invention illustrated herein, the portion of the forward end of the handle 16 from which the metal shank 2t} emerges is shaped to produce a surface of revolution 22 slightly smaller in diameter than the rest of the handle and adapted to releasably receive the complementary-shaped socket 24 in the adjacent extremity of the handle-forming portion 26 of the accessory. Quite obviously, surface of revolution 22 can be substantially cylindrical as shown, frusto-conical as long as the taper extends in the direction of the shank 2t), hemispherical or otherwise rounded and still perform the desired func 'tion of permitting both relative rotational and axial movement between the two elements that cooperate to produce the tool. The cylindrical surface of revolution 22 is preferred because it is simple to produce and, more important, when the two elements occupy the extended operative position of FIGURE 2, portion 22 bridges the gap separating the grooved surfaces that ordinarily adjoin one another and provides a continuous handgrip of approximately the same diameter.

The shank 20 of the driver is cylindrical and terminates in a blade 28 that is no wider than the diameter of the shank. Most, if not all, electrical screwdrivers are constructed with this type of blade; however, mention should be made of the point because wood and metalworking screwdrivers customarily have a broadened blade that would prevent removal of the accessory 14 and thus become unsuitable for use therewith. Thus, the modification, if any, in the conventional electricians screwdriver to accommodate the terminal-wiring accessory 14 would usually amount to nothing more than reforming the front end of the handle 16 to produce thereon the surface of revolution 22 that defines the plug adapted to fit into the correspondingly shaped socket 24 in the accessory while permitting both relative rotational and longitudinal movement therebetween.

Before proceeding with a detailed description of the accessory element 14, it would, perhaps, be desirable to refer briefly to FIGURE 5 and explain that it shows the same identical accessory used on a nut driver instead of a screwdriver. Accordingly, the only change in the driver 12 over that shown in FIGURES l and 2 is the substitution of a nut-receiving socket 30 in the end of the shank 20 in place of the bladed tip 28. Of course, it may be necessary to employ a larger diameter shank 20 for the nut driver and correspondingly larger tube 32 on the accessory because of socket 3ft but these are mere incidentals of construction that form no part of the invention. It is Worthy of note, however, that the socketed shank of the nut driver is also of uniform diameter to enable the accessory to be removed when not in use. Ordinarily, nut drivers are fabricated with a section of reduced diameter separating the socket-containing portion from the handle to save material and, for the reason already mentioned, such a construction is unsuitable for use with the accessory herein disclosed.

Next, with reference to the first four figures of the drawings, the terminal-wiring accessory or attachment for the driver will be described in detail. As has already been mentioned in passing, this accessory fitting comprises a handle-forming portion 26 having a tube 32 fastened therein that projects axially from the end 0pposite to that containing the socket 24. The axial opening 34 running the length of the tube communicates with the socket and is sized to receive the shank of the driver for free rotational and axial slidable movement. The front or free end of the tube is removed except for a small portion 36 thereof that projects and forms a finger. As shown, approximately three-fourths of the circumference of the end of the tube is removed back about a quarter to a half inch leaving finger 36 with an angular extent of or so. This finger is strong enough to withstand the forces exerted thereon when bending even heavy wire around a terminal post and the curvature thereof prevents same from being bent in a direction normal to the axis of the tube.

The opposite or rear end of the tube 32 is, in the particular form shown, cut out as at 38 leaving a gap for leaf spring 40 that partially encircles the driver shank 20 and bears there against to frictionally maintain the accessory in any desired adjusted relation relative to the driver. As best seen in FIGURE 4, one end of the spring 40 is merely brazed or otherwise fastened to an adjacent longitudinal edge of the tube 32 within the gap or notch 38. The spring-forming element 49 could, of course, be formed integrally from the tube wall provided the material from which the tube was fabricated is sufficiently springy or resilient.

The only other feature of tube 32 that has not been mentioned specifically is the ears 42 that are cast or otherwise imbedded into the plastic of the handle-forming portion 26 to insure that these elements turn together as a unit. Here again, many different constructions will acclclamplish this interlock and are in wide use commercia y.

The handle-forming portion 26 of the attachment 14- in essence forms a continuation of the driver handle 16 in that it is of the same outside diameter, has correspondingly shaped and arranged longitudinal grooves 18, and fits closely adjacent thereto when the plug portion 22 of the driver is fully seated in socket 24 of the attachment as shown in FIGURE 1. This handle-forming means also has a shallow annular groove 44 adjacent the forward extremity thereof that provides a gripping area for the users thumb and forefinger so that the attachment 14 can be rotated while the remaining fingers and palm of the hand hold the driver stationary.

In the retracted position of FIGURE 1, wherein the plug and socket portions are fully seated one within the other, the finger 36 is recessed behind the tip of the driver at least a distance sufficient to allow the blade to seat in the slot of a screw head. In the extended position of FIGURE 2, on the other hand, the finger 36 projects beyond the driver tip any distance needed to reach the bottom of the terminal post when the latter is anchored in the terminal strip. Note in FIGURE 2 that when the finger is extended to approximately the maximum degree that would ever be required in wrapping a conductor around a terminal post, only a small portion of the turned section 32 of the driver is based leaving a continuous gripping surface for the hand.

When wiring a terminal, the insulation is removed from the end of the conductor and this bared end placed alongside the threaded terminal post. Next the end of the driver is operatively engaged in the screw head or nut as the case maybe whereupon the attachment is extended with the thumb and forefinger and rotated, if necessary, to place the finger on the opposite side of the bared conductor end from the terminal post. In the final step, the conductor is wrapped a partial turn around the terminal post and the screw head or nut turned down tight on top thereof. In this final operation both the driver and attachment may be turned as a unit or, if desired, the attachment can be rotated a half turn or so between the thumb and forefinger while the rest of the hand holds the driver stationary. When this latter approach is taken, there is no danger of the gap closing between the fastener and strip before the conductor is fully inserted therebetween. Of course, in either instance, it is necessary to retract the attachment once again before the screw or nut can be turned down tight.

To remove the attachment it need only be slipped off over the end of the driver shank. The same attachment may be used for both a screw and nut driver in certain instances, i.e. large-headed screws and small nuts where both shanks can be the same diameter.

Having thus described the several useful and novel features of the terminal Wiring attachment for use in combination with screw and nut drivers that forms the subject matter of the present invention, it will be seen that the several worthwhile objectives for which it was designed have been achieved. Although but a single form of the attachment has been illustrated in the accompanying drawings, I realize that certain changes and modifications therein may well occur to those skilled in the art within the broad teaching hereof; hence, it is my intention that the comprising a handle-extending element with a central opening therethrough and a socket at one end thereof adapted to telescopically receive the plug end of the tool handle thus forming a continuation of the latter when mounted on the tool shank, a tubular element projecting axially from the handle-extending element along the shank which is received therein for both free relative rotational and reciprocal movement, and finger means located on the free end of the tubular element adapted upon rotational movement in extended reciprocal position to engage a bared end of a conductor and wrap same around a terminal post when the fastener-engaging end of the tool shank is in operative position atop said terminal post.

2. The combination as set forth in claim 1 in which the surface of revolution is cylindrical and of lesser diameter than the remainder of the tool handle.

3. The combination as set forth in claim 1 in which the fastener engaging means on the end of the shank comprises a screw driver blade no broader than the shank diameter.

4. The combination as set forth in claim 1 in which the fastener-engaging means on the end of the shank comprises a nut socket having an outside diameter no greater than the shank diameter.

5. The combination as set forth in claim 1 in which a spring is located inside the tubular element of the attachment, said spring being positioned and adapted to frictionally engage the tool shank and maintain the adjusted relation therebetween.

6. The terminal wiring attachment for hand tools of the type having a handle terminating in a cylindrical section at one end thereof and a cylindrical shank termimating in a fastener-driving tip projecting axially from the cylindrical section of the handle which comprises, a substantially cylindrical element having a central opening therethrough and a socket in one end thereof adapted to telescopically receive the cylindrical end of the driver handle forming an extension thereof when positioned on the driver shank, a tubular element projecting axially from the handle-extension element, said tubular element being adapted when receiving the driver shank to provide free relative rotational and reciprocal movement with respect thereto, and means located on the free end of the tubular element adapted upon rotational movement in extended reciprocal position to engage a bared end of a conductor and wrap same around a terminal post when the fastener-engaging end of the tool shank is in operative position atop said terminal post.

7. The attachment as set forth in claim 6 in which a spring is located inside the tubular element of the attachment, said spring being positioned and adapted to fric tionally engage the tool shank and maintain the adjusted relation therebetween.

References Cited by the Examiner UNITED STATES PATENTS 789,941 5/05 Sibley -124 2,546,489 3/51 Wright 140124 3,095,912 7/63 Sullivan 140-124 CHARLES W. LANHAM, Primary Examiner, 

1. IN COMBINATION: A HAND TOOL HAVING A HANDLE WITH A SURFACE OF REVOLUTION AT ONE END THEREOF FORMING A PLUG, A ROD-LIKE CYLINDRICAL SHANK PROJECTING AXIALLY FROM THE PLUG END OF THE HANDLE, AND DRIVER MEANS ADAPTED TO ENGAGE AND TURN A THREADED FASTENER LOCATED ON THE FREE END OF THE SHANK AND, AN ATTACHMENT FOR THE HAND TOOL COMPRISING A HANDLE-EXTENDING ELEMENT WITH A CENTRAL OPENING THERETHROUGH AND A SOCKET AT ONE END THEREOF ADAPTED TO TELESCOPICALLY RECEIVE THE PLUG END OF THE TOOL HANDLE THUS FORMING A CONTINUATION OF THE LATTE WHEN MOUNTED ON THE TOOL SHANK, A TUBULAR ELEMENT PROJECTING AXIALLY FROM THE HANDLE-EXTENDING ELEMENT ALONG THE SHANK WHICH IS RECEIVED THEREIN FOR BOTH FREE RELATIVE ROTATIONAL AND RECIPROCAL MOVEMENT, AND FINGER MEANS LOCATED ON THE FREE END OF THE TUBULAR ELEMENT ADAPTED UPON ROTATIONAL MOVEMENT IN EXTENDED RECIPROCAL POSITION TO ENGAGE A BARED END OF THE CONDUCTOR AND WRAP SAME AROUND A TERMINAL POST WHEN THE FASTENER-ENGAGING END OF THE TOOL SHANK IS IN OPERATIVE POSITION ATOP SAID TERMINAL POST. 